Hints that Amazon aims to increase its same-day delivery options have retailers of all sizes, from Wal-Mart to Shoptiques, scrambling to compete. The services required, however, are often money-losing and may not even be perks customers want, analysts say. "There's lots going on in this space, and it's all driven by Amazon," said Tom Allason, founder and CEO of Shutl, a U.K.-based delivery service.